What Hornbeck is doing in this verse is comparing Cates to famous people that went against the normal for the time. Socrates was a philosopher that had views of theology and philosophy that were very different from the ones that other philosophers of his time thought. He, like Cates, had arguments with the church about how he disagreed with it and taught something that was not accepted by the church. Dreyfus was also accused of doing something that was not entirely his fault. Romeo was in love with Juliet. But Juliet's father would not let her be with Romeo because of his family ties. This is the same for the ties that Rachel has. Her father is a pastor. So Rachel dating someone that does not believe in the way of God would be as controversial as Romeo dating Juliet.
Hornbeck is using an allusion in this part to stress the unfairness and the restrictions on the trial that is about to be had.
Hornbeck is using an allusion in this part to stress the unfairness and the restrictions on the trial that is about to be had.